In sanding a work surface with a portable power driven sanding tool, it is frequently desirable to deliver a flow of water to the work surface during the sanding operation, to act as a lubricant and coolant and wash away particles abraded from that surface. U.S. Pat. No. 5,022,190 issued Jun. 11, 1991 to Alma A. Hutchins shows a sander in which the water is fed to the work surface through passages in an orbitally driven head of the tool which carries a sheet of sandpaper. In my U.S. patent application Ser. No. 8/277,758 filed Jul. 20, 1994 on "Wet Sander", I have shown a sanding tool also having a head containing passages through which water is delivered to the work surface, and having a shroud disposed about the sanding head and within which a reduced pressure is created to withdraw air, water and particles from the work surface by suction as the work progresses.